Known in the art is a disposable diaper which is provided with a single torso opening and a pair of leg openings, which disposable diaper is provided with a front part and back part which are separated from each other in the length direction when the diaper is spread open and with an elastic sheet which is joined with these front part and back part, the side edge regions of the front part and back part being joined by tape fasteners (see PLT 1). If doing this, the elastic sheet contacts the wearer, so the diaper easily follows movement of the wearer and slippage of the diaper downward can be suppressed.